1. Field of Invention
The invention relates to a separation roller of a document or sheet feeder, and a sheet separating mechanism using the same, and more particularly to a miniaturized separation roller which can be easily replaced and repaired, and a sheet separating mechanism using the same.
2. Related Art
FIG. 1 is a schematic illustration showing a first conventional sheet separating mechanism. Referring to FIG. 1, the sheet separating mechanism includes a sheet transporting roller 101, a friction pad 102 and a spring 103. The sheet S is disposed between the sheet transporting roller 101 and the friction pad 102. The spring 103 presses the friction pad 102 in a direction toward the sheet transporting roller 101. Thus, when multiple sheets enter a passageway 104 between the sheet transporting roller 101 and the friction pad 102, the friction pad 102 stops the sheet S contacting therewith so that the sheet separating effect can be achieved. However, when a last sheet is being fed by this sheet separating mechanism, the sheet rubs against the friction pad 102 for a long period of time, and the sheet or the friction pad tends to be worn.
FIG. 2 is a schematic illustration showing a second conventional sheet separating mechanism. Referring to FIG. 2, the sheet separating mechanism includes a sheet transporting roller 201, a separation roller 202, a spring 203 and a torque limiter 204. The torque limiter 204 is mounted on a shaft assembly 205 and is disposed in the separation roller 202 to provide a torsional force to achieve the sheet separating effect. In this sheet separating mechanism, this separation roller 202 has to accommodate the torque limiter 204, so its size cannot be reduced. In addition, the processes of disassembling and assembling the torque limiter 204 are more complicated. Thus, the user or maintenance man feels inconvenient when he or she is replacing the separation roller 202.
In another conventional separation roller assembly, a separation roller frame is mounted on a shaft and connected to a torque limiter. The torque limiter connected to the separation roller provides a torsional force to achieve the sheet separating effect. However, the user or the maintenance man may feel inconvenient when he or she is replacing the separation roller. In addition, because the width of this separation roller assembly cannot be effectively shortened, the separation roller assembly cannot be miniaturized.